go/internal/srcimporter: skip tests on iOS

The iOS test harness only includes the current test directory in its
app bundles, but the tests need access to all source code.

Change-Id: I8a902b183bc2745b4fbfffef867002d573abb1f5
Reviewed-on: https://go-review.googlesource.com/37961
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/go/internal/srcimporter/srcimporter_test.go

@@ -76,7 +76,7 @@ func walkDir(t *testing.T, path string, endTime time.Time) (int, bool) {
 }
 
 func TestImportStdLib(t *testing.T) {
-	if runtime.GOOS == "nacl" {
+	if !testenv.HasSrc() {
 		t.Skip("no source code available")
 	}
 
@@ -102,7 +102,7 @@ var importedObjectTests = []struct {
 }
 
 func TestImportedTypes(t *testing.T) {
-	if runtime.GOOS == "nacl" {
+	if !testenv.HasSrc() {
 		t.Skip("no source code available")
 	}
 
@@ -134,7 +134,7 @@ func TestImportedTypes(t *testing.T) {
 }
 
 func TestReimport(t *testing.T) {
-	if runtime.GOOS == "nacl" {
+	if !testenv.HasSrc() {
 		t.Skip("no source code available")
 	}
 

src/internal/testenv/testenv.go

@@ -114,6 +114,19 @@ func HasExec() bool {
 	return true
 }
 
+// HasSrc reports whether the entire source tree is available under GOROOT.
+func HasSrc() bool {
+	switch runtime.GOOS {
+	case "nacl":
+		return false
+	case "darwin":
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			return false
+		}
+	}
+	return true
+}
+
 // MustHaveExec checks that the current system can start new processes
 // using os.StartProcess or (more commonly) exec.Command.
 // If not, MustHaveExec calls t.Skip with an explanation.